Core does not publish a catalogue of platform events yet. There is no stable
set of domain events an extension can subscribe to, and this page will not
invent one. What exists today is the flow-level event mechanism described
below.
Flow events
A flow emits an event through theemit_event node. Emission is queued rather
than synchronous — QueuedFlowTriggerEventPublisher hands it to the
scheduled.triggers queue, so a flow that emits does not wait for whatever
consumes the event.
Triggers
What an event causes is resolved through the trigger contracts infapost/foundation:
Trigger fan-out runs on
scheduled.triggers, separate from message handling, so a
broad fan-out cannot delay a conversation — see Queues.
Analytics
Analytics is a distinct stream, not the event bus. It is written throughAnalytics\Contracts\AnalyticsWriterInterface with AnalyticsEvent and
AnalyticsEventType, and it exists to record what happened rather than to
trigger behaviour.
History
Flow\History\HistoryEventType enumerates the event kinds recorded against a
flow session’s history. It is a record of session progression, readable after the
fact — not a subscription surface.
If you need to react to something
Today that means a node handler on the flow, or a registered schedule — see Building a Plugin. If the reaction you need cannot be expressed either way, that is a missing contract infapost/foundation, and the
right move is to propose it rather than to hook into a Core internal that carries
no stability promise.